02.Salt and high blood pressure
High blood pressure is often called the ‘silent killer’ because there are no obvious symptoms — but the higher your blood pressure, the greater the risk of having a stroke or heart attack.
There’s now very good evidence that too much salt is a major cause of high blood pressure:
- A high salt intake is associated with an increased risk of developing high blood pressure as you get older.
- If you already have high blood pressure a low-salt diet can lower it.
- If you’re on blood-pressure-lowering medication, a low-salt diet can boost the effect and you may be able to take less (but check with your GP first).
Shake the salt habit
The National Health and Medical Research Council’s Dietary Guidelines for Australian Adults recommend that you choose foods low in salt and cut back to no more than about 6 g of salt a day (a bit over a teaspoonful, amounting to around 2.3 g of sodium). But it’s not as easy as it sounds, because about 75% of the salt in many people’s food comes hidden in processed foods and takeaways and you don’t know how much of it you’re eating.
We checked the sodium levels (which are given on labels in milligrams rather than grams) in some of the foods in the CHOICE standard grocery basket that we use to compare supermarket prices (see the Sodium savings, table). If you ate a serve of all these foods over a day they’d give you about 3500 mg of sodium — considerably more than the maximum daily intake of 2300 mg (2.3 g) recommended by the Dietary Guidelines for Australian Adults.
Often there are low-salt or reduced-salt versions. Choosing these could save you nearly 2000 mg of sodium and bring the total to well below the recommended maximum (see the table for details).
Particular foods to watch are:
Bread. On average about 25% of our salt intake comes from bread. You can buy low-salt bread but you may have to search for it.
Breakfast cereals. Many popular brands have far too much salt (see Breakfast cereals for details). Muesli is usually a good choice.
- Foods such as bacon, sausages and most cheeses, where salt is traditionally used as a preservative.
Soups, tinned vegetables and sauces can be loaded with salt. There can be big differences between brands, so check the labels.
Cakes and biscuits can be surprisingly salty. Again it varies a lot from brand to brand, so check the labels. Our shopping basket contains ARNOTT’S Tim Tam biscuits, which are relatively low in salt (170 mg of sodium per 100 g), but if you bought ARNOTT’S Tiny Teddy Chocolate biscuits instead, you’d be getting 390 mg of sodium per 100 g.
Food labels now make it easier to choose foods with less salt. The nutrition information panel must tell you the amount of sodium (rather than salt) in the food you’re eating (see the salt-sodium connection).
To compare products it’s best to use the amount per 100 g rather than the amount per serve, as serving sizes can vary. But don’t agonise over small differences (50 mg or so). These numbers are only averages and the actual sodium levels from batch to batch could easily differ from those stated on the label by as much 20%. Low-salt foods must have less than 120 mg sodium per 100 g of the food.